1. Field of the Invention
The present invention relates to a common mode choke coil, and more particularly to a common mode choke coil for eliminating noise flowing out of an electronic appliance.
2. Description of Related Art
A common mode choke coil generally has a component of normal mode leakage inductance even a little, and thereby, the common mode choke coil is effective to eliminate normal mode noise. However, if normal mode noise is strong, not only the common mode choke coil but also a normal mode choke coil is necessary to eliminate noise.
On the other hand, if the common mode choke coil has a relatively large component of normal mode leakage inductance, the leakage magnetic flux therefrom badly influences the adjacent circuits. In this case, it is necessary to provide a magnetic shield around the common mode choke coil.